In order to secure a safety in a driving operation of a fastener, an accidental-ejection preventing mechanism is widely used in the related art in which the fastener is not launched only by a control of pulling a trigger lever, and fastener driving can be performed by pressing a contact arm disposed at the tip of a tool.
However, the fastener driving operation is often performed by pressing the contact arm against a driven member in the state of pulling the trigger lever, and thus the contact arm may contact an unintended portion to operate a fastener driving machine.
For this reason, it is prevented that the contact arm is pressed when the contact arm contacts the unintended portion by taking an action that protrudes the contact arm with a spring having high load, which improves the reliability of preventing an accidental ejection. However, there is a problem that a burden on the operator increases since a usual operation load increases.
JP-A-5-57635 describes a driving tool in which a human body detection sensor including a pyroelectric-type infrared ray sensor, an ultrasonic sensor, a capacitive sensor, or the like is embedded in a lower end surface of a guide plate guiding a lower end of a striker. In the driving tool, when the human body detection sensor detects a human body, the driving of the staple is stopped although a main switch is turned on.
JP-A-9-239674 describes a nailing machine in which a pyroelectric-type infrared ray sensor for detecting infrared ray emitted from a human body is provided in the front side of a nose portion including an injection outlet of a nail, and when it is recognized that the human body is present in a direction of injecting a nail, the striking mechanism is not operated although a trigger and the contact arm are erroneously controlled.
Japanese Patent No. 3132330 describes a nailing machine in which an acceleration sensor is mounted in a mechanism housing as a body of the nailing machine. The nailing machine is configured such that in a case where an acceleration pattern and a moving direction, which is stored in advance, of the nailing machine moving toward a driving target object in an injection direction do not match with an acceleration and a moving direction detected by the acceleration sensor, a nail is not launched although a fastener driving control is performed.